Reduce spawn rates on EVERYTHING

[AugustT]

Esp. Squids and birds

[GPowney]

I've updated this to increase the spawn rate slightly! Mainly for the test map for now.

[AugustT]

How slightly is slightly? We could have this as a parameter in the code?

[GPowney]

I played with the spawn rates, and have them at a good level. It'll update when I push the latest commits. Still to sort here:

• What is happening with the cats? Why do they disappear?!
• Add in some birds. Perhaps start with the grey colour form as they look a bit like pigeons!